Xtbimmihg d device



L. B. PIERSON.

TRIMIVIING DEVICE.

APPLICATION FILED APR. 9 1919.

15 i w.) INVENTOR 1/ i, g ///%M 1 v ,5 A? f mTORNEYS.

TED srATns- "PATEN OFFICE.

tours a. rrnnsonr, or cnrcornn rants, massncnusnrrs, assist-on ro rein rrsK nunnnn COMPANY, or crrrcornn FALLS, MASSACHUSETTS, a conrona'rroii' or MASSAGHUSF'JLTS.

leas es.

n i To all whom at may concern:

Be it known that'll, Louis B. Pierson, a

citizen of the United States of America, re-

following is a specification.

My invention relates to power operated cutting or trimming devices, and has particular reference to poweroperated devices for trimming the overflow from the tread of an automobile tire casing, and also for. trimming the fin, or surplus material, from the inside edge of the bead ofsuch a casing.

It has for its object the provision of a power operated cutter to take the place of the hand knife now employed for these Pill]?! poses, and the increase in the speed with which tire casings may be trimmed.

Further objects will appear from a consideration of its description and use,

Referring to the drawings in which like numerals'refer to like parts throughout:

Figure 1 is a perspective view of a trimming device embodying my invention;

Fig. 2 is a transverse section therethrough, taken on line 2-2 of Fig. l;

Fig. 3 is a sectional plan, taken ,on line 3 8 of Fig. 2; Y

Fig. 4. 's a longitudinal section, talzen online M of Fig. 2; a r

Fig. 5 is a perspective view of the slide carrying the movable cutting member; and

Fig. 6 is a fragmentary perspective view of one of the cutting members.

"lhe fined miife or cutting member if) is fastened to a forwardly projecting part 11 till of a bloclt 12, forming the body of the device. The bottom 13 of the block is preferably substantially flat, although itmay be shaped to fit the work if desired, and serves as a guide to direct the cuttersinto roper relation. to the art of the work whic is to be trimmed. s shown, the bottom 13 is beveled oflji' slightly on its rearward side to assist pro erly guiding the cutter when the inner eges of tire heads are being trimmed. Attachment of the lznife to the block may bemade in any suitable manner, as by a screw it or by welding.

. -'llhe movable hnife 15 is secured, as by a screw 16 passing through a countersunk hole 17 in the knife, to a projection 18 ofa slide 19, or it maybe secured thereto by welding.

Specification of Letters Patent.

Application ar a Apri19,19l9. Serial No. aseraa Patented Dec. 23, 1919.

The knives are preferably set in the form of a V, as shown, so as to give a shearing out. One side of the block 12 has a slot 20 in which this slide moves, and the other side of the block has holes 21. furnishing bearing for two guide members 22 which extend laterally from the slide. bored as at '23, to receive ca screws 24 secured to the ends of gui e, member 22. Springs 25 between the heads of these cap screws and the inner end of the counterbore serve to urge the cutting members toward each other, as is evident from Fig. 3. These springs are desirable to take up lost motion, and are necessary if a cam be substituted for the eccentric described'below, but may he dispensed with, together with the counthe outer ends of the counterbores.

Holes 21 are counterterbores and cap screws, if desired, in the The interior of the block 12 is, chambered,

as shown, at 27, for the 'pur ose of receiving the driving mechanism or reciprocating the cutters. in the present embodiment this driving mechanism consists of an cecentric 28, mounted on a vertical shaft 29. A strap 30 encircles the eccentric, and a lug Bill 31 thereon is ivoted by a pin 32 to suitable lugs 33 on side "19. Shaft Q9 is driven from a, shaft 3i hybevel gears 35 and 36.

Shaft 34 passes freely through a handle 37,

attached'to block 12, and terminates in, a flexible portion 38, which may be connected to any suitable source of power, such as an electric motor.

'lhe resent embodiment of my invention is particularly designed for trimming the fin or overflow occurring at the center of the tread of an automobile tire casing on account of the use of'ia split mold in the vulcanization of the casing; and also for trim- Fll ming the sharp edge at. the inside of the beads of the casings. in both these instances it is necessary that the cutters shall remove only the part regarded as waste material, and shallnot cut into and injure the body of the casing. ll prevent this accident in two ways. First, it should be noted that the lengths of the cutting surfaces are short relatively to the length of the guide surface 13. lhis prevents the cutters being accidentally tipped overso as to out into the tire, and at the same time insures a sufficient hearin surface to make the cut re lar and even sound, as an additional sa eguardQ'I provide the cutting members with rounded and blunted ends 39, effectually preventing the points of the cutters from digging in to the tire. The provision of these rounded and blunted portions enables the device to be pressed much. more firmly against the work than would be the case if the ends Were left sharp.

I realize that changes may be made in the details shown while preserving the same function and result, and consider such changes to be within the scope of my invention as set forth in the appended claims. For example, a cam upon shaft 29 can be substituted for the eccentric shown, a suitable abutment being provided on slide 19.

I claim- 1. lin a device of the character described,

cured to the slide, both of the cutting members being substantially in line with the the shaft, and a second knife secured to the slide.

3. A trimming device having a body portion, a knife secured thereto, a slide mounted for movement in the body portion, a shaft in the body portion, an eccentric on the shaft, a strap encircling the eccentric and connected to the slide, a bevel gear on the shaft, a shaft at an angle to the first shaft, a bevel gear on the second shaft, meshing with the first mentioned 'gear, a handle attached to the body portion and encircling; the second mentioned shaft, and a second knife secured to the slide.

LGUIS B. PIERSON. 

